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cutaneous PEComa

Wednesday 19 March 2008

PEComas represent a family of uncommon mesenchymal tumors composed of “perivascular epithelioid cells” with a distinct immunophenotype that typically shows both myogenic and melanocytic differentiation.

The PEComa family includes angiomyolipoma (AML), clear cell “sugar” tumor of the lung and extra pulmonary sites, lymphangioleiomyomatosis and clear cell myomelanocytic tumor of the falciform ligament/ligamentum teres. Very rarely, PEComas may arise in the skin.

Primary cutaneous PEComas typically display a dermal proliferation of epithelioid cells with pale, clear, or granular pink cytoplasm arranged in nests and trabeculae with an intervening arborizing network of delicate capillaries.

Primary cutaneous PEComas have a lower frequency of myogenic marker expression than their deep soft tissue and visceral counterparts.

They also often express strong diffuse CD10, leading to potential confusion with metastatic renal cell carcinoma. Most cases behave indolently.

Images

 Primary cutaneous PEComa (perivascular epithelioid cell tumor) CD10+ HMB45+

Differential diagnosis

 cutaneous clear cell tumors

See also

 PEComa : perivascular epithelioid cell tumor / PVECT

Paywall References

 Primary cutaneous perivascular epithelioid cell tumor (PEComa): Five new cases and review of the literature. 2017. doi : 10.1111/cup.12972

 Liegl B, Hornick JL, Fletcher CD. Primary Cutaneous PEComa: Distinctive Clear Cell Lesions of Skin. Am J Surg Pathol. 2008 Feb 14; PMID: 18277881